code: def custom_function(a, b):
      return a + b
  
imports: import re
  import sys
  import pytest
  import nni
  import nni.trial
  import torch
  import pytorch_lightning
  from nni.mutable import Categorical, Numerical, SampleValidationError
  from nni.mutable.mutable import _mutable_equal
  from nni.nas.evaluator import FunctionalEvaluator
  from nni.nas.evaluator.pytorch import Classification, Lightning, DataLoader, Trainer, LightningModule
  from nni.nas.evaluator.evaluator import FrozenEvaluator
  from torch import nn
  from torch.utils.data import TensorDataset
label_desc: Use image node_id 3 for calling a global function with example usage: custom_function(a, b) and returns: unknown